Featured Research

from universities, journals, and other organizations

More Meteorites May Hit Earth Than Supposed: New Tool Gives A Recount

Date:

November 25, 2008

Source:

University of Alberta

Summary:

Researchers have found a tool that could reveal possibly hundreds of undiscovered craters across Canada and around the world. As more craters are found and analyzed existing theories on how many meteorites have hit Earth in the past and the frequency of future impacts will change.

Related Articles

The discovery of a meteorite crater near Whitecourt, 200 kilometers west of Edmonton, Alberta, Canada prompted Chris Herd to examine the site from the air using existing aerial surveys. A computer program, applied to aerial images taken by a forestry company, stripped away the images of trees to expose the landscape, revealing the meteorite crater.

Herd, an assistant professor in the U of A's department of earth and atmospheric sciences, says this technology can be used to potentially reveal hundreds of meteorite craters around the world that are hidden by trees but unknowingly captured on aerial forest surveys.

Herd believes that as more craters are found and analyzed existing theories on how many meteorites have hit Earth in the past and the frequency of future impacts will change.

Herd's research will be published in the journal, Geology, on Nov. 25.

But he's unleashed new technology that could prove meteorite impacts with Earth aren't as rare as we think.

Herd agrees that "yes," a giant meteorite, almost 10 kilometres wide, likely ended the age of the dinosaurs, but will it happen again? "Something that big only happens every tens of millions of years," he said. "It's possible, but only remotely."

If you're counting, the so-called dinosaur-killing meteorite hit Earth 65 million years ago.

And about the Nov. 20 meteorite, estimated to be the size of an office desk, which blazed across the prairie sky and landed somewhere in Saskatchewan? Herd is confident we're safe. "The chances of actually being hit by a meteorite are almost incalculable," he said.

Putting meteorite impacts in perspective was a major concern this week as Herd released details of a new technique to locate undiscovered meteorite craters. The breakthrough came when Herd analyzed a meteorite crater near Whitecourt, 200 kilometers west of Edmonton.

Herd and his colleagues decided they needed an aerial view of the 36 meter-wide crater. "You can't spot it from the air because of the trees," He said, although the solution was close at hand. "We bought Light Detection and Ranging aerial images of the area that already existed."

LiDAR equipment is attached to an aircraft and beams of laser light capture 3-D images of the ground below. The forest industry uses the technology to count trees and determine the topography, but Herd wasn't interested in the trees.

"We asked for the Bare Earth model," he said. "That's terrain with the images of the trees and vegetation stripped away."

It was the breakthrough Herd was hoping for. The image of Whitecourt meteorite crater was clear as day.

Herd sees a bright future for crater counting. "We should be able to look through LiDAR data from wherever it's been acquired and find more undiscovered craters."

Current theories on Earth impacts say meteorites the size and age of the rock that made the crater near Whitecourt happen every 10 years. That's every 10 years for the last 10,000 years. When scientists adjust the numbers to account for meteorite hits in oceans and crater evidence erased by land erosion Herd is still encouraged.

"There should be dozens, maybe a hundred, meteorite craters like Whitecourt."

A meteorite crater can tell a scientist when it came to Earth and what it was made of.

The Whitecourt meteorite fell to Earth about 11 hundred years ago. Herd estimates it was about a meter wide. He knows the rock was composed of iron and nickel and that it started its journey through space in the core of a 4.5 billion year old Asteroid. That Asteroid broke apart and pieces of the core became meteorites. So far only half a dozen meteorite craters the age and size of the Whitecourt site have been located.

To find more of them Herd and others are negotiating access for more existing LiDAR surveys. He's already getting tips from people on where to start looking. "People are calling and say they remember seeing a bowl shaped depression in the Earth and we're building a file based on those accounts."

While some people might be looking skyward these days with a little concerned these are great times for Herd.

"I can't get enough of it. Meteorites are all good with me."

Story Source:

The above story is based on materials provided by University of Alberta. The original article was written by Brian Murphy. Note: Materials may be edited for content and length.

University of Alberta. "More Meteorites May Hit Earth Than Supposed: New Tool Gives A Recount." ScienceDaily. ScienceDaily, 25 November 2008. <www.sciencedaily.com/releases/2008/11/081125141600.htm>.

University of Alberta. (2008, November 25). More Meteorites May Hit Earth Than Supposed: New Tool Gives A Recount. ScienceDaily. Retrieved March 3, 2015 from www.sciencedaily.com/releases/2008/11/081125141600.htm

University of Alberta. "More Meteorites May Hit Earth Than Supposed: New Tool Gives A Recount." ScienceDaily. www.sciencedaily.com/releases/2008/11/081125141600.htm (accessed March 3, 2015).

More From ScienceDaily

More Earth & Climate News

Featured Research

Mar. 3, 2015 — Attendance at schools exposed to high levels of traffic-related air pollution is linked to slower cognitive development among 7- to 10-year-old children in Barcelona, according to a new ... full story

Mar. 3, 2015 — While studying a ground-nesting bird population near El Reno, Okla., a research team found that stress during a severe weather outbreak of May 31, 2013, had manifested itself into malformations in ... full story

Mar. 3, 2015 — Researchers studied quartz from the San Andreas Fault at the microscopic scale, the scale at which earthquake-triggering stresses originate. The results could one day lead to a better understanding ... full story

Mar. 3, 2015 — The 3-D printing scene, a growing favorite of do-it-yourselfers, has spread to the study of plasma physics. With a series of experiments, researchers have found that 3-D printers can be an important ... full story

Mar. 3, 2015 — Researchers have developed a new way of rapidly screening yeasts that could help produce more sustainable biofuels. The new technique could also be a boon in the search for new ways of deriving ... full story

Mar. 3, 2015 — For almost a century, scientists have been puzzled by a process that is crucial to much of the life in Earth's oceans: Why does calcium carbonate, the tough material of seashells and corals, ... full story

Mar. 3, 2015 — Major cities in the UK are falling behind their international counterparts in terms of their use of smart technologies, according to a new study. The research has found that smart cities in the UK, ... full story

Mar. 3, 2015 — To simulate chimp behavior, scientists created a computer model based on equations normally used to describe the movement of atoms and molecules in a confined space. An interdisciplinary research ... full story

Mar. 3, 2015 — Rather than just waiting patiently for any pollinator that comes their way to start the next generation of seeds, some plants appear to recognize the best suitors and 'turn on' to increase the chance ... full story

Featured Videos

Looted and Leaking, South Sudan's Oil Wells Pose Health Risk

AFP (Mar. 3, 2015) — Thick black puddles and a looted, leaking ruin are all that remain of the Thar Jath oil treatment facility, once a crucial part of South Sudan&apos;s mainstay industry. Duration: 01:13
Video provided by AFP

Related Stories

July 31, 2014 — Physicists have tested what would happen if a piece of rock containing microscopic fossils from Earth was launched into space and hit the surface of the moon. The team turned fossil-filled rock into ... full story

May 27, 2014 — Impact craters reveal one of the most spectacular geologic process known to human beings. During the past 3.5 billion years, it is estimated that more than 80 bodies, larger than the dinosaur-killing ... full story

May 1, 2013 — In an effort to determine if conditions were ever right on Mars to sustain life, a team of scientists has examined a meteorite that formed on the Red Planet more than a billion years ... full story

May 24, 2012 — Molecules containing large chains of carbon and hydrogen -- the building blocks of all life on Earth -- have been the targets of missions to Mars from Viking to the present day. While these molecules ... full story

Aug. 1, 2011 — Is Earth more likely or less likely to be hit by an asteroid or comet now as compared to, say, 20 million years ago? Several studies have claimed to have found periodic variations, with the ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.